IntroductionThe purpose of this work was to study the prognostic influence in breast cancer of thioredoxin reductase 1 (TXNRD1) and thioredoxin interacting protein (TXNIP), key players in oxidative stress control that are currently evaluated as possible therapeutic targets.MethodsAnalysis of the association of TXNRD1 and TXNIP RNA expression with the metastasis-free interval (MFI) was performed in 788 patients with node-negative breast cancer, consisting of three individual cohorts (Mainz, Rotterdam and Transbig). Correlation with metagenes and conventional clinical parameters (age, pT stage, grading, hormone and ERBB2 status) was explored. MCF-7 cells with a doxycycline-inducible expression of an oncogenic ERBB2 were used to investigate the influence of ERBB2 on TXNRD1 and TXNIP transcription.ResultsTXNRD1 was associated with worse MFI in the combined cohort (hazard ratio = 1.955; P < 0.001) as well as in all three individual cohorts. In contrast, TXNIP was associated with better prognosis (hazard ratio = 0.642; P < 0.001) and similar results were obtained in all three subcohorts. Interestingly, patients with ERBB2-status-positive tumors expressed higher levels of TXNRD1. Induction of ERBB2 in MCF-7 cells caused not only an immediate increase in TXNRD1 but also a strong decrease in TXNIP. A subsequent upregulation of TXNIP as cells undergo senescence was accompanied by a strong increase in levels of reactive oxygen species.ConclusionsTXNRD1 and TXNIP are associated with prognosis in breast cancer, and ERBB2 seems to be one of the factors shifting balances of both factors of the redox control system in a prognostic unfavorable manner.

Background: Real-time reverse transcriptase quantitative polymerase chain reaction (real-time RTqPCR) is the most accurate measure of gene expression in biological systems. The comparison of different samples requires the transformation of data through a process called normalisation. Reference or housekeeping genes are candidate genes which are selected on the basis of constitutive expression across samples, and allow the quantification of changes in gene expression. At present, no reference gene has been identified for any organism which is universally optimal for use across different tissue types or disease situations. We used microarray data to identify new reference genes generated from total RNA isolated from normal and osteoarthritic canine articular tissues (bone, ligament, cartilage, synovium and fat). RTqPCR assays were designed and applied to each different articular tissue. Reference gene expression stability and ranking was compared using three different mathematical algorithms.

Circulating tumor cells (CTCs) exist in the peripheral blood stream of metastatic cancer patients at rates of approximately 1 CTC per billion background cells. In order to capture and analyze this rare cell population, various techniques exist that range from antibody-based surface marker positive selection to methods that use physical properties of CTCs to negatively exclude background cells from a CTC population. However, methods to capture cells for functional downstream analyses are limited due to inaccessibility of the captured sample or labeling techniques that may be prohibitive to cell function. Here, we present a negative selection method that leverages a microfluidic cell concentrator (MCC) to allow collection and analysis of this rare cell population without needing cell adhesion or other labeling techniques to keep the cells within the chamber. Because the MCC is designed to allow collection and analysis of non-adherent cell populations, multiple staining steps can be applied in parallel to a given CTC population without losing any of the population. The ability of the MCC for patient sample processing of CTCs for enumeration was demonstrated with five patient samples, revealing an average of 0.31 CTCs per mL. The technique was compared to a previously published method – the ELISPOT – that showed similar CTC levels among the five patient samples tested. Because the MCC method does not use positive selection, the method can be applied across a variety of tumor types with no changes to the process.

Purpose: Members of the Bcl-2 family act as master regulators of mitochondrial homeostasis and apoptosis. We analyzed whether ERBB2 influences the prognosis of breast cancer by influencing the proapoptotic versus antiapoptotic balance of Bcl-2 family members.Experimental Design: ERBB2-regulated Bcl-2 family members were identified by inducible expression of ERBB2 in MCF-7 breast cancer cells and by correlation analysis with ERBB2 expression in breast carcinomas. The prognostic relevance of ERBB2-regulated and all additional Bcl-2 family members was determined in 782 patients with untreated node-negative breast cancer. The biological relevance of ERBB2-induced inhibition of apoptosis was validated in a murine tumor model allowing conditional ERBB2 expression.Results: ERBB2 caused an antiapoptotic phenotype by upregulation of MCL-1, TEGT, BAG1, BNIP1, and BECN1 as well as downregulation of BAX, BMF, BNIPL, CLU, and BCL2L13. Upregulation of the antiapoptotic MCL-1 [P = 0.001, hazard ratio (HR) 1.5] and BNIP3 (P = 0.024; HR, 1.4) was associated with worse prognosis considering metastasis-free interval, whereas clusterin (P = 0.008; HR, 0.88) and the proapoptotic BCL2L13 (P = 0.019; HR, 0.45) were associated with better prognosis. This indicates that ERBB2 alters the expression of Bcl-2 family members in a way that leads to adverse prognosis. Analysis of apoptosis and tumor remission in a murine tumor model confirmed that the prototypic Bcl-2 family member Bcl-x L could partially substitute for ERBB2 to antagonize tumor remission.Conclusions: Our results support the concept that ERBB2 influences the expression of Bcl-2 family members to induce an antiapoptotic phenotype. Antagonization of antiapoptotic Bcl-2 family members might improve breast cancer therapy, whereby MCL-1 and BNIP3 represent promising targets. Clin Cancer Res; 16(2); 451-60. ©2010 AACR.

Immunoassays are utilized for a wide variety of clinical and biomedical research applications. In typical immunoassays, analytes are captured, labeled, and quantified on a single surface (e.g., the bottom of a well plate). In order to minimize the background, this type of assay must be washed multiple times between each of these steps to ensure residual reagents (e.g., unbound labeling antibody) are removed from the system. In this manuscript, the immunoassay is fundamentally reconfigured, such that each reagent is confined to its own well and no wash steps are required. Using immiscible filtration assisted by surface tension (IFAST), a technique developed for nucleic acid and whole cell purifications, immunoassays can be drastically simplified such that all reagent manipulation is performed at the start of the assay (i.e., no pipetting steps are necessary during the assay). Analytes are bound to paramagnetic particles via antibodies and drawn through oil barriers between four isolated compartments: (1) sample well, (2) primary antibody labeling well, (3) secondary antibody labeling well, and (4) readout buffer well. Using this technique, we have demonstrated repeatable detection of as little as 188 fg of protein. IFAST immunoassay functionality is demonstrated by detecting a well accepted prostate cancer biomarker, prostate specific antigen (PSA). Assay performance was assessed by measuring known concentrations of recombinant PSA protein. The assay was then used to measure PSA concentrations in conditioned media and human plasma samples.

Originally identified in cultured cells, oncogenic cellular senescence is a growth-arrest mechanism which may inhibit tumor development by limiting the ability of cells to divide. However, literature shows that these cells secrete tumor-inducing and tumor-suppressing proteins leading to poor prognosis. Understanding the progression of oncogenic cellular senescence and associated mechanisms provides important implications for improving tumorigenesis therapeutic treatments. Micro-Raman spectroscopic imaging has grown in popularity as an imaging technique compared to the standard imaging predecessors and can be attributed to its numerous benefits such as no sample perturbation and the provision of direct chemical information. Through the use of label-free micro-Raman spectroscopy, control and senescent cells were noninvasively imaged. Resulting spectral images were processed using chemometric techniques, and average nuclei spectra from each sample set were compared. In turn, changes in the -cis and -trans unsaturated lipid isomer content were found to differ among proliferating and senescent cells. This may lead to increased nuclear fluidity and may contribute to the inability of senescent cells to complete the cell cycle. In the tumor environment, this detected increase in nuclear envelope fluidity could lead to downstream gene expression modifications and increased nucleo-cytoplasmic RNA translocation. Understanding nuclear envelope fluidity could provide insight into secretory profiles of senescent cells and their role in carcinogenesis, meriting further investigation into novel therapeutic technique development for oncogenic cellular senescence.

Recent studies have presented evidence that in vivo obtained gene expression data can be used for carcinogen classification, for instance to differentiate between genotoxic and non-genotoxic carcinogens. However, although primary rat hepatocytes represent a well-established in vitro system for drug metabolism and enzyme induction, they have not yet been systematically optimized for toxicogenomic studies. The latter may be confounded by the fact that cultured hepatocytes show strong spontaneous alterations in gene expression patterns. Therefore, we addressed the following questions: (1) which culture system is optimal, comparing sandwich, Matrigel and 2D cultures, (2) how critical is the impact of culture period on substance-induced alterations in gene expression and (3) do these substance-induced alterations in cultured hepatocytes occur already at in vivo relevant concentrations? For this purpose we analyzed the expression of four genes, namely Abat, Gsk3beta, Myd116 and Sult1a1 that recently have been reported to be influenced by the antihistamine and non-genotoxic carcinogen methapyrilene (MPy). The most reproducible effects of MPy were observed in sandwich cultures. Induction factors of Gsk3beta and Myd116 at 100 microM MPy were 2 and 4 (medians), respectively, whereas expression of Abat and Sult1a1 were inhibited by factors of 7 and 5, respectively. Similar results were observed in hepatocytes maintained for 24 h or 3 weeks in sandwich culture with respect to the influence of MPy on the expression of Abat, Gsk3beta, Myd116 and Sult1a1. To determine whether MPy influences gene expression at in vivo relevant concentrations, 3.5 mg/kg MPy were administered to male Wistar rats intraperitoneally, resulting in plasma concentrations ranging between 1.72 and 0.32 microM 5 and 80 min after injection. Inhibition of Abat and Sult1a1 expression in vitro already occurred at in vivo relevant concentrations of 0.39 microM MPy. Induction of Myd116 was observed at 6.25 microM which is higher but in the same order of magnitude as in vivo relevant concentrations. In conclusion, the presented data strongly suggest that sandwich cultures are most adequate for detection of MPy-induced gene expression alterations and the effect of MPy was detected at in vivo relevant concentrations.

Recently, epithelial to mesenchymal transition (EMT) has been shown to represent a feature of dedifferentiating hepatocytes in vitro. Three-dimensional soft collagen gels can antagonize but not completely abolish this effect. Hormonal additives to culture media are known to maintain differentiated hepatocyte functions. Therefore, we studied whether insulin and dexamethasone antagonize EMT in cultured hepatocytes. Both hormones antagonized but not completely abolished certain morphological features of EMT. Dexamethasone antagonized acquisition of fibroblastoid shape, whereas insulin favored bile canaliculi formation. In a subsequent step, we analyzed expression of a battery of EMT-related genes. Of all markers tested, vimentin and snail-1 correlated best with morphological features of EMT. Interestingly, dexamethasone reduced expression levels of both vimentin and snail-1, whereas the influence of insulin was less pronounced. An important result of this study is that 12 out of 17 analyzed EMT markers were transcriptionally influenced by dexamethasone (vimentin, snail-1, snail-2, HNF4 alpha, Twist-1, ZEB2, fibronectin, occludin, MMP14, claudin-1, cytokeratin-8, and cytokeratin-18), whereas the remaining factors seemed to be less dependent on dexamethasone. In conclusion, EMT markers in hepatocytes can be classified as dexamethasone-dependent versus -independent.